estimated yield of 4 kg. per hectare (22.2 

 pounds per acre). If shrimp that were removed 

 from the pond had survived and grown at the 

 same rate as those remaining, harvest esti- 

 mates would be doubled, or 8 kg. per hectare 

 (44.4 pounds per acre). 



After ternnination of the initial study, we 

 flushed, refilled, and restocked the circulating- 

 water pond with one-half of the shrimp popu- 

 lation from the static -water pond. This "trans - 

 plant" was made to determine the possible 

 growth response of stunted shrimp to feeding. 

 Food was provided and withheld during alter- 

 nate periods. This study demonstrated that 

 growth could be accelerated or retarded at 

 will by either supplying or withholding food, 

 and furthermore that this response was rapid. 



An interesting aspect of the pond culture 

 arose when a few postlarvae of white shrimp 

 were inadvertently placed in the static-water 

 pond with the postlarvae of brown shrimp. 

 Although data on growth of white shrimp were 

 limited, the average lengths and weights at- 

 tained in 120 days were spectacular when 

 connpared with brown shrimp (table 1). These 

 results suggest that it may be more feasible 

 to rear white shrimp them brown shrimp under 

 seminatural conditions. 



Table 1. --Average length and number of white 

 Eind brown shrimp per kilogram after a 120- 

 day growing period under identical condi- 

 tions 



Preparations were made in the spring of 

 1966 to rear both brown and white shrimp 

 in mass culture from eggs spawned in the 

 laboratory. Gravid female shrimp collected 

 offshore so far, however, have failed to spawn 

 in the ponds. 



Ray S. Wheeler, Project Leader 



ECOLOGICALLY ASSOCIATED 

 ORGANISMS 



During the last half of 1965, we tabulated 

 data on 30 species of fish commonly taken in 

 experimental shrimp trawling at 7 to 110 nn. 

 along the Texas and Louisiana coasts in 

 1 962-64. A report on the seasonal, bathymetric, 



and relative abundance of each species is 

 nearing connpletion. 



To supplement the data on finfish in the 

 same ecological habitat as the white, brown, 

 and pink shrimp in the northwestern Gulf of 

 Mexico, we began in January 1966 to study 

 the epifauna (organisms living on the oceain 

 floor) and infauna (organisms living in the 

 bottom sediments) of the offshore commercial 

 shrimping grounds. Considerable time has 

 been spent reviewing the literature, con- 

 ferring with others engaged in the same type 

 of research, and testing various kinds of 

 sampling gear. This preliminary work is to 

 be followed by systematic sampling along the 

 Texas coast to obtain quantitative and qualita- 

 tive estimates of the bottom fauna. 



Although our initial sampling was designed 

 primarily for testing gear, one series of 

 samples was obtained along a transect extend- 

 ing seaward off Galveston. Samples were taken 

 at depths from 5 to 37 m. with a sled-type 

 dredge designed to sample the top 1.3 cm. of 

 the substrate. The analysis of these samples 

 indicated that the greatest catch of all orga- 

 nisms combined per unit effort was inshore; 

 catches decreased with increase in depth 

 (fig. 4). Conversely, the number of species 

 taken increased with an increase in depth. 

 MoUusks dominated--the hauls had 20 families 

 of snails (Gastropoda) and bivalves (Pele- 

 cypoda). To date, we have identified 48 species 

 of snails and 38 species of bivalves, and a 

 reference collection has been established. 



To complement the investigation of bottom 

 fauna, studies have also begun on the food 

 habits of shrimp and the more abundant fish 

 species. Contents of the stomachs of two 

 species of shrimp and four species of fish 

 taken during the winter are listed in table 2. 

 Although data are limited, it appears that the 



10 20 30 



PEHCENT OF Tor»L C4TCM 



Figure 4. — Percentage occurrence by depth of bottom 

 Invertebrate groups collected off Galveston, Tex., 

 January-February 1966. 



